#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#if 0

#define N         2048    /* size of ring buffer */
#define F           33    /* upper limit for match_length */
#define THRESHOLD    1  /* encode string into position and length
                           if match_length is greater than this */
#define NIL            N    /* index for root of binary search trees */

unsigned long int
textsize = 0,    /* text size counter */
codesize = 0,    /* code size counter */
printcount = 0;    /* counter for reporting progress every 1K bytes */
unsigned char
text_buf[N + F - 1];    /* ring buffer of size N,
						with extra F-1 bytes to facilitate string comparison */
int        match_position, match_length,  /* of longest match.  These are
										  set by the InsertNode() procedure. */
										  lson[N + 1], rson[N + 257], dad[N + 1];  /* left & right children &
																				   parents -- These constitute binary search trees. */

void InitTree(void)  /* initialize trees */
{
	int  i;

	/* For i = 0 to N - 1, rson[i] and lson[i] will be the right and
	left children of node i.  These nodes need not be initialized.
	Also, dad[i] is the parent of node i.  These are initialized to
	NIL (= N), which stands for 'not used.'
	For i = 0 to 255, rson[N + i + 1] is the root of the tree
	for strings that begin with character i.  These are initialized
	to NIL.  Note there are 256 trees. */

	for (i = N + 1; i <= N + 256; i++) rson[i] = NIL;
	for (i = 0; i < N; i++) dad[i] = NIL;
}

void InsertNode(int r)
/* Inserts string of length F, text_buf[r..r+F-1], into one of the
trees (text_buf[r]'th tree) and returns the longest-match position
and length via the global variables match_position and match_length.
If match_length = F, then removes the old node in favor of the new
one, because the old one will be deleted sooner.
Note r plays double role, as tree node and position in buffer. */
{
	int  i, p, cmp;
	unsigned char  *key;

	cmp = 1;  key = &text_buf[r];  p = N + 1 + key[0];
	rson[r] = lson[r] = NIL;  match_length = 0;
	for (;;) {
		if (cmp >= 0) {
			if (rson[p] != NIL) p = rson[p];
			else { rson[p] = r;  dad[r] = p;  return; }
		}
		else {
			if (lson[p] != NIL) p = lson[p];
			else { lson[p] = r;  dad[r] = p;  return; }
		}
		for (i = 1; i < F; i++)
			if ((cmp = key[i] - text_buf[p + i]) != 0)  break;
		if (i > match_length) {
			match_position = p;
			if ((match_length = i) >= F)  break;
		}
	}
	dad[r] = dad[p];  lson[r] = lson[p];  rson[r] = rson[p];
	dad[lson[p]] = r;  dad[rson[p]] = r;
	if (rson[dad[p]] == p) rson[dad[p]] = r;
	else                  lson[dad[p]] = r;
	dad[p] = NIL;  /* remove p */
}

void DeleteNode(int p)  /* deletes node p from tree */
{
	int  q;

	if (dad[p] == NIL) return;  /* not in tree */
	if (rson[p] == NIL) q = lson[p];
	else if (lson[p] == NIL) q = rson[p];
	else {
		q = lson[p];
		if (rson[q] != NIL) {
			do { q = rson[q]; } while (rson[q] != NIL);
			rson[dad[q]] = lson[q];  dad[lson[q]] = dad[q];
			lson[q] = lson[p];  dad[lson[p]] = q;
		}
		rson[q] = rson[p];  dad[rson[p]] = q;
	}
	dad[q] = dad[p];
	if (rson[dad[p]] == p) rson[dad[p]] = q;  else lson[dad[p]] = q;
	dad[p] = NIL;
}

unsigned int mygetc(unsigned char** input){
	unsigned char r = **input;
	(*input)++;
	return r;
}

void myputc(unsigned int r, unsigned char** input){
	**input = r;
	(*input)++;
}

int encode(unsigned char *inputBuf, int length, unsigned char *outputBuf)
{
	int  i, c, len, r, s, last_match_length, code_buf_ptr;
	unsigned char  code_buf[17], mask;

	int offset = 0;
	int result = 0;

	unsigned char *outputBufStart = outputBuf;
	unsigned char *inputBufEnd = inputBuf + offset + length;
	inputBuf += offset;

	InitTree();  /* initialize trees */
	code_buf[0] = 0;  /* code_buf[1..16] saves eight units of code, and
					  code_buf[0] works as eight flags, "1" representing that the unit
					  is an unencoded letter (1 byte), "0" a position-and-length pair
					  (2 bytes).  Thus, eight units require at most 16 bytes of code. */
	code_buf_ptr = mask = 1;
	s = 0;  r = N - F;
	for (i = s; i < r; i++) text_buf[i] = '\0';  /* Clear the buffer with
												 any character that will appear often. */
	for (len = 0; len < F && (c = *(inputBuf++), inputBuf <= inputBufEnd); len++)
		text_buf[r + len] = c;  /* Read F bytes into the last F bytes of
								the buffer */
	if ((textsize = len) == 0) return NULL;  /* text of size zero */
	for (i = 1; i <= F; i++) InsertNode(r - i);  /* Insert the F strings,
												 each of which begins with one or more 'space' characters.  Note
												 the order in which these strings are inserted.  This way,
												 degenerate trees will be less likely to occur. */
	InsertNode(r);  /* Finally, insert the whole string just read.  The
					global variables match_length and match_position are set. */
	do {
		if (match_length > len) match_length = len;  /* match_length
													 may be spuriously long near the end of text. */
		if (match_length <= THRESHOLD) {
			match_length = 1;  /* Not long enough match.  Send one byte. */
			code_buf[0] |= mask;  /* 'send one byte' flag */
			code_buf[code_buf_ptr++] = text_buf[r];  /* Send uncoded. */
		}
		else {
			code_buf[code_buf_ptr++] = (unsigned char)match_position;
			code_buf[code_buf_ptr++] = (unsigned char)
				(((match_position >> 3) & 0xe0)
				| (match_length - (THRESHOLD + 1)));  /* Send position and
													  length pair. Note match_length > THRESHOLD. */
		}
		if ((mask <<= 1) == 0) {  /* Shift mask left one bit. */
			for (i = 0; i < code_buf_ptr; i++)  /* Send at most 8 units of */
			{
				myputc(code_buf[i], &outputBuf);    /* code together */
				result++;
			}
			codesize += code_buf_ptr;
			code_buf[0] = 0;  code_buf_ptr = mask = 1;
		}
		last_match_length = match_length;
		for (i = 0; i < last_match_length &&
			(c = *(inputBuf++), inputBuf <= inputBufEnd); i++) {
			DeleteNode(s);        /* Delete old strings and */
			text_buf[s] = c;    /* read new bytes */
			if (s < F - 1) text_buf[s + N] = c;  /* If the position is
												 near the end of buffer, extend the buffer to make
												 string comparison easier. */
			s = (s + 1) & (N - 1);  r = (r + 1) & (N - 1);
			/* Since this is a ring buffer, increment the position
			modulo N. */
			InsertNode(r);    /* Register the string in text_buf[r..r+F-1] */
		}
		if ((textsize += i) > printcount) {
			//            printf("%12ld\r", textsize);  
			printcount += 1024;
			/* Reports progress each time the textsize exceeds
			multiples of 1024. */
		}
		while (i++ < last_match_length) {    /* After the end of text, */
			DeleteNode(s);                    /* no need to read, but */
			s = (s + 1) & (N - 1);  r = (r + 1) & (N - 1);
			if (--len) InsertNode(r);        /* buffer may not be empty. */
		}
	} while (len > 0);    /* until length of string to be processed is zero */
	if (code_buf_ptr > 1) {        /* Send remaining code. */
		for (i = 0; i < code_buf_ptr; i++)
		{
			myputc(code_buf[i], &outputBuf);
			result++;
		}
		codesize += code_buf_ptr;
	}


	//    myputc(0, &outputBuf);
	//free(outputBufStart);

	return result;
}

int decode(unsigned char *inputBuf, int length, unsigned char *outputBuf)    /* Just the reverse of Encode(). */
{
	int  i, j, k, r, c;
	unsigned int  flags;

	int offset = 0;
	int result = 0;
	unsigned char *outputBufStart = outputBuf;
	unsigned char *inputBufEnd = inputBuf + offset + length;
	inputBuf += offset;

	for (i = 0; i < N - F; i++) text_buf[i] = '\0';
	r = N - F;  flags = 0;
	for (;;) {
		if (((flags >>= 1) & 256) == 0) {
			c = *(inputBuf++);
			if (inputBuf > inputBufEnd)
				break;
			flags = c | 0xff00;        /* uses higher byte cleverly */
		}                            /* to count eight */
		if (flags & 1) {
			c = *(inputBuf++);
			if (inputBuf > inputBufEnd)
				break;
			myputc(c, &outputBuf);
			result++;
			text_buf[r++] = c;
			r &= (N - 1);
		}
		else {
			i = *(inputBuf++);
			if (inputBuf > inputBufEnd)
				break;
			j = *(inputBuf++);
			if (inputBuf > inputBufEnd)
				break;
			i |= ((j & 0xe0) << 3);  j = (j & 0x1f) + THRESHOLD;
			for (k = 0; k <= j; k++) {
				c = text_buf[(i + k) & (N - 1)];
				myputc(c, &outputBuf);
				result++;
				text_buf[r++] = c;
				r &= (N - 1);
			}
		}
	}

	return result;
}


#endif 
